News / Publications » Publications

Molds in Buildings



What are molds?: Molds are a group of plants called fungi reproduce by creating tiny spores that float through the air.

Health Effects: Allergic responses include asthma and hay fever-type symptoms such as a runny nose and red eyes. Exposure to mold can irritate the eyes, skin, nose and throat.

Prevention: Find and correct conditions that cause moisture to enter and buildup in a building. Remove building materials and furnishings that have been damaged by mold.

Laws: Currently, there are no federal standards or recommendations for exposure limits to airborne mold or mold spores.


What are molds?

Molds are a group of plants called fungi that can be found indoors and outdoors. There are tens of thousands or possibly hundreds of thousands of different molds. They grow best in warm, damp, and humid conditions. Molds reproduce by creating tiny spores that float through the air. Outdoors, molds break down organic matter such as toppled trees, fallen leaves, and dead animals. They are necessary to produce certain foods and medicines such as cheese and penicillin. Indoors, mold growth can cause health problems.

When are molds a problem?

Mold growth will often occur when there is excessive moisture or water accumulates within a building. There are molds that grow on wood, paper, carpet, and insulation, as well as dust and dirt that gather in moist areas of a building. Problems can arise when mold starts eating away at these materials, affecting their look and smell. They can cause serious harm to the structure of wood-framed buildings.

What are the health effects of molds?

Molds produce allergens that can cause allergic reactions in some people. Reactions can appear right away or develop over time. Allergic responses include asthma and hay fever-type symptoms such as a runny nose and red eyes. Exposure to mold can irritate the eyes, skin, nose and throat. Symptoms other than allergic and irritant types are not commonly reported as a result of inhaling mold in the indoor environment.

How can mold problems be prevented or corrected?

Moisture problems in buildings have been linked to changes in construction practices since the 1970s that have resulted in tightly sealed buildings and poor ventilation. While it is impossible to eliminate all molds and mold spores, minimizing moisture can control indoor mold growth. Sources of moisture include water leaks through roofs and window seals, landscaping, gutters that direct water into or under a building, and space heaters or other appliances that are not equipped with ventilation.

Mold Prevention and Control Measures

The key to preventing and/or controlling the growth of molds is to address moisture problems.

  • Repair plumbing, roof, or other leaks as soon as possible.
  • Find and correct causes of condensation and wet spots.
  • Locate and fix sources of moisture seepage into the building.
  • Perform regular inspections and maintenance of the heating, ventilation and air conditioning (HVAC) system, including filter changes.
  • Keep HVAC drip pans clean and flowing properly.
  • Keep indoor relative humidity below 70% (25 - 60%, if possible) and increase air circulation.
  • Vent appliances that produce moisture, such as dryers, to the outside.
  • Vent kitchens and bathrooms according to local code requirements.
  • Clean and dry wet or damp spots as soon as possible, but no more than 48 hours after they are discovered. Thoroughly clean, dry and/or remove water-damaged materials.

Correcting mold problems

The first step is to find and fix the conditions that lead to mold growth. After assessing the extent of the problem, materials damaged by mold may need to be removed (remediation). Employers must use workers who have been trained for mold remediation or hire a qualified contractor. When selecting a contractor is important to check references and require them to follow the recommendations in the Environmental Protection Agency's publication, "Mold Remediation in Schools and Commercial Buildings" or similar guidelines. The workplan should include steps to carefully contain and remove moldy building materials in a manner that will prevent further contamination, and the use of personal protective equipment (PPE).

Are there federal laws exist to protect workers from molds?

There are no federal laws or recommendations for exposure to airborne mold or mold spores.

May 2004

For more information about protecting workers from workplace hazards, contact the AFSCME Health and Safety Program at (202) 429-1215, or 1625 L Street, N.W., Washington, DC 20036.

Get news & updates from AFSCME